code: def get_file_size(filename, cache={}):
      if filename in cache:
          return cache[filename]
      file_size = int(os.popen("wc -l < %s" % filename).read())
      cache[filename] = file_size
      return file_size
  
file_path: vowpal_wabbit/test/save_resume_test.py
imports: import sys
  import os
  import optparse
  import random
  from itertools import zip_longest
label_desc: Use image node_id 4 for calling a global function with example usage: get_file_size(filename, cache) and returns: file_size, cache